This document provides an overview of pathology including definitions, key figures, scope, and core aspects. It discusses cellular adaptations like hypertrophy, hyperplasia, atrophy, and metaplasia. Cell injury mechanisms like free radicals and apoptosis are explained. Necrosis is contrasted with apoptosis. Intracellular accumulations from abnormal metabolism or deficiencies are also summarized. The document aims to explain pathology from a molecular to clinical level.
Different drug regularity bodies in different countries.
Cellular injury and adaptation
1. Antecedents
Group no. 01
Group Members:
Rana Ahmed (PHA-14001)
Mahfujul Hasan (PHA-14002)
Shahida Yeasmin Sima (PHA-14005)
Shamima Akter Sumi (PHA-14007)
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2. Contents
Introduction to Pathology
Definition
Father of Modern Pathology
Scope
Core aspects
Cellular Injury and Adaptation
Stages of the cellular response
Adaptation
Hypertrophy
Hyperplasia
Atrophy
Metaplasia
Cell injury
Intracellular Accumulations
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3. What Is Pathology
• Pathology is the study (logos) of diseases (pathos).
• The study of the structural, biochemical and functional changes in
cells, tissues and organs that underlie diseases.
• It attempts to explain sign and symptoms by use of
Molecular
Microbiologic
Immunologic
Morphologic techniques
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4. Rudolf Virchow
Father of Modern Pathology
“Virtually all forms of tissue injury
starts with molecular or structural
alterations in CELLS”
1821-1902
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5. The Scope of Pathology
Scientific knowledge about human diseases from observations on
patients or by from experimental studies.
Explain the whys and wherefores of signs and symptoms expressed.
It offers clinical care and therapy.
It serves as the bridge between basic sciences and clinical medicine.
Pathology is the foundation for all medicine.
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6. Core aspects of pathology
There are four aspects of diseases process that form the core of
pathology. These are following-
1. Etiology
2. Pathogenesis
3. Molecular and morphological changes
4. Clinical manifestations
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11. Stages of the Cellular Responses
Fig: Stages of the cellular response to stress and injurious stimuli
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12. Adaptation
Adaptations are reversible changes in the size, number, phenotype,
metabolic activity or functions of cells in response to changes in their
environment.
Four types of adaptation are occurred-
• Hypertrophy
• Hyperplasia
• Atrophy
• Metaplasia
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13. Hypertrophy
• Hypertrophy is an increase in the size of cells resulting in an increase
in the size of the organ.
• There are no new cells, just large cells.
• Hypertrophy can be physiologic or
pathologic.
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17. Hyperplasia
• Hyperplasia is an increase in the number of cells in an organ or
tissue, resulting in increased mass of the organ or tissue.
• Hyperplasia can be physiologic or pathologic.
• In both situations, cellular proliferation is stimulated by growth
factors that are produced by a variety of cell types.
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18. Types
Physiologic hyperplasia
1. Hormonal hyperplasia:
The proliferation of the glandular epithelium of
the female breast at puberty and during
pregnancy.
2. Compensatory hyperplasia:
When part of a liver is resected, mitotic activity in
the remaining cells begins as early as 12 hours
later, eventually restoring the liver to its normal
size.
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19. Pathologic Hyperplasia
Most forms of pathologic hyperplasia are caused by excesses of
hormones or growth factors acting on target cells.
Example:
Endometrial hyperplasia is an example of abnormal hormone
induced hyperplasia.
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20. Mechanisms of Hyperplasia
Hyperplasia is the result of growth factor, driven proliferation of
mature cells.
In some cases, by increased output of new cells from tissue stem
cells.
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21. Atrophy
• Atrophy is reduced size of an organ or tissue resulting from a
decrease in cell size and number.
• Atrophy represents a reduction in the structural components of the
cell.
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22. Common Causes of Atrophy
Decreased workload
Loss of innervation
Diminished blood supply
Inadequate nutrition
Loss of endocrine stimulation
Pressure
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23. Mechanisms of Atrophy
Atrophy results from decreased
protein synthesis and increased
protein degradation in cells.
Reduction metabolic activity.
Nutrient deficiency activates
ubiquitin ligases.
Autophagy
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24. Metaplasia
• Metaplasia is a reversible change in which one differentiated cell type
is replaced by another cell type.
• The most common epithelial metaplasia is columnar to squamous, as
occurs in the respiratory tract in response to chronic irritation.
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25. Mechanisms of Metaplasia
• Reprogramming of stem cells that are known to exist in normal
tissues.
• The precursor cell differentiated along a new pathway, signaled by
cytokines, growth factor and components of the cell in this
environment.
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26. Cell injury
• If the adaptive capability is
exceeded or if the external
stress is inherently harmful or
excessive, cell injury develops.
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27. Causes of Cell Injury
• Oxygen Deprivation
• Physical Agents
• Chemical Agents and Drugs
• Infectious Agents
• Immunologic Reactions
• Genetic Derangements
• Nutritional Imbalances
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30. Apoptosis
• Apoptosis is a pathway of cell death that is induced by a tightly
regulated suicide program in which cells destined to die activate
enzymes that degrade the cells own nuclear DNA and nuclear and
cytoplasmic proteins.
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31. CAUSES OF APOPTOSIS
Apoptosis in Physiologic Situations
Apoptosis serves to eliminate cells that are no longer needed and to
maintain a steady. It is important in the following physiologic situations:
The programmed destruction of cells during embryogenesis
Involution of hormone-dependent tissues upon hormone
withdrawal
Cell loss in proliferating cell populations
Elimination of potentially harmful self-reactive lymphocytes
Death of host cells that have served their useful purpose
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32. Apoptosis in Pathologic Conditions
Apoptosis eliminates cells that are injured beyond repair without
eliciting a host reaction, thus limiting collateral tissue damage.
DNA damage
Accumulation of mis-folded proteins
Cell death in certain infections
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33. MORPHOLOGIC AND BIOCHEMICAL
CHANGES IN APOPTOSIS
• Cell shrinkage
• Chromatin condensation
• Formation of cytoplasmic blebs and
apoptotic bodies
• Phagocytosis of apoptotic cells by
macrophages.
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34. Necrosis
• Necrosis is a form of
cell death in which
cellular membranes
fall apart and cellular
enzymes leak out and
ultimately digest the
cell.
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36. Intracellular Accumulations
• Under some circumstances, cells may accumulate abnormal amounts
of various substances, which may be harmless or may cause varying
degrees of injury.
• The substances fall into two categories:
Normal cellular constituents
ex: Water, lipids, proteins etc.
Abnormal substances
ex: Products of infectious agents, abnormal
synthesis/metabolism.
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37. Mechanisms of intracellular
accumulation
1. Abnormal metabolism
2. Mutations causing
alterations in protein
folding and transport
3. A deficiency of critical
enzymes
4. Inability to degrade
phagocytosed particles
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38. Various components of intracellular
accumulation
A. Depositions of lipids
a. Fatty change
b. Cholesterol deposition
B. Deposition of proteins
C. Deposition of glycogens
D. Deposition of pigments
E. Pathologic calcifications
a. Dystrophic calcification
b. Metastatic calcification
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